Compensation watch balance and hair spring.



No. 669,763. Patented Mar. l2, I901. P. FERRET.

COMPENSATION WATCH BALANCE AND HAIR SPRING.

(Application filed Nov. 26, 1897.]

[No Model.)

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PAUL FERRET, OF OHAUX-DE-FONDS, SWITZERLAND.

COMPENSATION WATCH BALANCE AND HAIR SPRING.

SPECIFICATION forming part of Letters Patent N 0. 669,763, dated March 12, 1901.

Application filed November 26, 1897. Serial No. 659,880;- (No model.)

To aZZ whom, it may concern.-

Be it known that I, PAUL FERRET, manufacturer, a citizen of the Swiss Republic, residing at OhauX-de-Fonds, Switzerland, have invented certain new and useful Improvements in Escapements for Watches, Clocks, and the Like, (which have been patented in Switzerland by Letters Patent No. 14,270, dated May 6, 1897,) of which the following is a specification.

This invention relates to improvements in all kinds of escapements for watches, clocks, and the like; and it consists, mainly, in the combination of a balance or hair spring made of an alloy formed of about seventy -two parts, by Weight, of steel and about twentyeight parts, by Weight, of nickel, with an ordinary balance-that is to say, a non-compensation balancemade of brass. The increase in elastic force of the balance-spring formed of this alloy with the rise of temperature is just sufficient to compensate for the increase of the moment of inertia of the balance due to its expansion.

In the accompanying drawing I have shown an ordinary or non-compensation balance adapted to operate in connection with my improved balance'spring.

In the drawing, a, designates the balancespring, and Z) is the balance-wheel, made of brass.

In this specification the term nickel signifies commercial nickel and not chemicallypure metal, and the term brass signifies all alloys of copper which have nearly the same coeficient of expansion as the usual brass.

WVhat I claim is- The combination of a non-compensation balance made of brass, with a balance-spring of the usual form made of an alloy formed of about seventy-two parts by weight of steel and about twenty-eight parts by Weight of nickel and Having-the property of increasing its lastic force with a rise of temperature just sufficiently for obtaining a compensation for the expansion of the uncompensated balance.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

PAUL FERRET.

Witnesses ARMAND FEERELET, EPHRIAM HUGUENIN. 

